Problems with double-blind RCTs

Perhaps the most influential and rigorous of these early studies was the Good Friday experiment, conducted in 1962 by Walter Pahnke, a psychiatrist and minister working on a Ph.D. dissertation under Leary at Harvard. In a double-blind experiment, twenty divinity students received a capsule of white powder right before a Good Friday service at Marsh Chapel, on the Boston University campus; ten contained psilocybin, ten an active placebo (nicotinic acid). Eight of the ten students receiving psilocybin reported a mystical experience, while only one in the control group experienced a feeling of “sacredness” and a “sense of peace.” (Telling the subjects apart was not difficult, rendering the double-blind a somewhat hollow conceit: those on the placebo sat sedately in their pews while the others lay down or wandered around the chapel, muttering things like “God is everywhere” and “Oh, the glory!”) Pahnke concluded that the experiences of eight who received the psilocybin were “indistinguishable from, if not identical with,” the classic mystical experiences reported in the literature by William James, Walter Stace, and others.